1. Field of the Invention
The present invention relates generally to communication networks and, more particularly, to topology-optimized networks that include directional, wireless nodes that are not fixed in space.
2. Description of the Related Art
A communication network typically includes a collection of hardware components interconnected by communication channels that provides for sharing of resources and information. Each point in the communication channel where data can be received and/or transmitted is referred to as a node. In a computer network, a node may be a modem, bridge, switch or host computer. In a cellular telecommunications network, a node may be the base station controller, home location register or GPRS support nodes. Network topology, or the interconnections of nodes within a network, may be optimized in different ways. For example, a network may be optimized to route information in the shortest amount of time or in a way that minimizes the overall power drain on the network.
Nodes may be wired or wireless. Wired nodes are connected with other nodes via a wired connection. Examples of wired nodes include land line telephones and computers connected to a network via an Ethernet cable. A wireless node is a node that is connected with other nodes via a wireless connection. Examples of wireless nodes include cellular telephones and computers connected to a network via a wireless connection.
An example conventional wired network will now be described with reference to FIGS. 1-2.
FIG. 1 illustrates a conventional network 100 of wired communication nodes fixed in space.
As shown in the figure, nodes 102-126 are connected to each other via communication channels 128-178. In this configuration, there are many different paths by which information can be shared between nodes 102-126. For example, node 102 may connect with node 110 via communication channels 146, 152, and 158. Alternatively, node 102 may connect with node 110 via communication channels 144, 168, 176 and 160. It can be appreciated that a connection between any pair of nodes 102-126 may be accomplished by a number of different paths that travel along communication channels 128-178.
A central control node 102 contains all of the information about the network via communications with the other nodes in network 100. Typically, central control node 102 will monitor all other nodes in the network by polling the other nodes for information at predetermined intervals. Central control node 102 controls the path of information through the network by optimizing parameters such as connectivity, power consumption, network traffic, or other parameters known in the art. In an example scenario, central control node 102 may route information through conventional network 100 in such a way to minimize communication time between nodes 104 and 114. This will be described in more detail with reference to FIG. 2.
FIG. 2 illustrates an optimal connection path 200 between the wired communication nodes of network 100 of FIG. 1.
As shown in FIG. 2, connection path 200 is imposed by central control node 102 based on optimizing parameters such as connectivity, power consumption, network traffic, or other parameters known in the art. In an example scenario, central control node 102 routs information via connection path 200 in order to minimize communication time between nodes 104 and 114. Information can flow between nodes 104 and 114 in one of two paths. Path one comprises communication channels 148, 150, 132, 156, 158, 136, 162, and 164. Path two comprises communication channels 128, 144, 168, 166, and 140. Other communication channels and nodes from FIG. 1 are not shown because central control node 102 prevents communication through those nodes and along those communication channels.)
Similar network optimization is conventionally performed for wireless networks. This will be described in greater detail with reference to FIGS. 3-4.
FIG. 3 illustrates a conventional network 300 of wireless communication nodes fixed in space.
As shown in the figure, nodes 302-326 are connected to each other via communication channels 328-352. In this configuration, there are many different paths by which information can be shared between nodes 302-326. For example, node 302 may connect with node 318 via communication channels 352, 336, and 340. Alternatively, node 102 may connect with node 110 via communication channels 350, 348, and 344. It can be appreciated that a connection between any pair of nodes 302-326 may be accomplished by a number of different paths that travel along communication channels 328-352.
A central control node 302 contains all of the information about the network via communications with the other nodes in network 300. Typically, central control node 302 will monitor all other nodes in the network by polling the other nodes for information at regular, known intervals. Central control node 302 controls the path of information through the network based on optimizing parameters such as connectivity, power consumption, network traffic, or other parameters known in the art. In an example scenario, central control node 302 may route information through conventional wireless network 300 in such a way to minimize communication time between nodes 304 and 318. This will be described in more detail with reference to FIG. 4.
FIG. 4 illustrates an optimal connection path 400 between the wireless communication nodes of network 300 of FIG. 3.
As shown in FIG. 4, connection path 400 is imposed by central control node 302 based on optimizing parameters such as connectivity, power consumption, network traffic, or other parameters known in the art. In an example scenario, central control node 302 routes information via connection path 400 in order to minimize communication time between nodes 304 and 318. Information can flow between nodes 304 and 318 in one of many paths. One path comprises wireless communication channels 354, 334, and 344. Another path comprises wireless communication channels 346 and 344. Other paths between nodes 304 and 318 are possible based on other combinations of wireless communication channels 334, 344, 346 and 354, however all paths are optimal paths based on the objective to minimize communication time between nodes 304 and 318. Other communication channels from FIG. 3 are not shown because central control node 302 prevents communication along those communication channels.
A conventional communication network may include a mixture of wired nodes, as described above with reference to FIGS. 1-2, and wireless nodes, as described above with reference to FIGS. 3-4. Additionally, a central control node may be either wired or wireless, so long as it has the ability to monitor all nodes within the network in order to optimize performance based on predetermined parameters.
A wireless node may be directional or non-directional. A non-directional, wireless node is one that broadcasts its signal without directionality, such that any other node within a 360 degree radius, and within the broadcast area, can receive the signal. A directional, wireless node is one that broadcasts its signal with directionality, such that another node must be within a radius that is less than 360 degrees, and within the broadcast area, in order to receive the signal. The direction in which a directional node transmits its signal is not fixed; the direction can be changed to reach other nodes in other areas.
A conventional communication system may include a mixture of wired, non-directional wireless and directional wireless nodes. This will be described with reference to FIGS. 5-6.
FIG. 5 illustrates a conventional network 500 of wired, non-directional wireless and directional wireless communication nodes fixed in space.
As shown in the figure, nodes 502 and 506 are directional wireless nodes. The wireless signals 504 and 508 of nodes 502 and 506, respectively, are not broadcast 360 degrees from nodes 502 and 506. Instead, wireless signals 504 and 508 are broadcast in a specific direction. For example, wireless signal 504 can reach wired node 512 but it cannot reach wired node 514 based on the current orientation of wireless signal 504. The direction of wireless signals 504 and 508 can be changed, so wireless signals 504 and 508 may reach different nodes at different times.
Node 510 is a non-directional wireless node that is the central control node of network 500. As shown in the figure, wireless signal 516 of node 510 is broadcast 360 degrees from node 510. In contrast to wireless signals 504 and 508, wireless signal 516 does not require rotation in order to reach other nodes within its broadcast area. Central control node 510 controls the path of information through the network by optimizing parameters such as connectivity, power consumption, network traffic, or other parameters known in the art.
There may be situations where a directional node is not fixed in space, but is mobile. In such situations, it may not be possible to continuously optimize a network having moving nodes, as it may not be possible for the central control node to communicate with such nodes at all times. This will be described in greater detail with reference to FIG. 6.
FIG. 6 illustrates network 500 of FIG. 5 where wireless, directional node 502 is not fixed in space, but is mobile.
As shown in FIG. 6, while node 502 is in communication with, for example, nodes 512 and 514 via wireless signal 504, central control node 510 still contains all of the global information about the network, including the physical location of node 502. However, when wireless signal 504 is directed away from the rest of the nodes in network 500, central control node 510 does not have any information regarding node 502, including its physical location, and is therefore unable to compute an optimal information path or optimal node topology using all of the nodes in network 500.
The lack of communication between nodes described above is undesirable, and a conventional network utilizing a central control node does not provide for topology optimization of a network that includes directional, wireless nodes that are not fixed in space.
What is needed is a system and method to allow for topology optimization of a network that includes directional, wireless nodes that are not fixed in space.